Class JComboBox<E>
- Type Parameters:
E- the type of the elements of this combo box
- All Implemented Interfaces:
ActionListener,ImageObserver,ItemSelectable,MenuContainer,Serializable,EventListener,Accessible,ListDataListener
Warning: Swing is not thread safe. For more information see Swing's Threading Policy.
Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing. As of 1.4, support for long term storage
of all JavaBeans
has been added to the java.beans package.
Please see XMLEncoder.
See How to Use Combo Boxes in The Java Tutorial for further information.
- Since:
- 1.2
- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected classThis class implements accessibility support for theJComboBoxclass.static interfaceThe interface that defines aKeySelectionManager.Nested classes/interfaces declared in class javax.swing.JComponent
JComponent.AccessibleJComponentNested classes/interfaces declared in class java.awt.Container
Container.AccessibleAWTContainerNested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy -
Field Summary
FieldsModifier and TypeFieldDescriptionprotected StringThis protected field is implementation specific.protected ComboBoxModel<E> This protected field is implementation specific.protected ComboBoxEditorThis protected field is implementation specific.protected booleanThis protected field is implementation specific.protected JComboBox.KeySelectionManagerThis protected field is implementation specific.protected booleanThis protected field is implementation specific.protected intThis protected field is implementation specific.protected ListCellRenderer<? super E> This protected field is implementation specific.protected ObjectThis protected field is implementation specific.Fields declared in class javax.swing.JComponent
listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOWFields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENTFields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH -
Constructor Summary
ConstructorsConstructorDescriptionCreates aJComboBoxwith a default data model.Creates aJComboBoxthat contains the elements in the specified array.Creates aJComboBoxthat contains the elements in the specified Vector.JComboBox(ComboBoxModel<E> aModel) Creates aJComboBoxthat takes its items from an existingComboBoxModel. -
Method Summary
Modifier and TypeMethodDescriptionvoidThis method is public as an implementation side effect.protected voidactionPropertyChanged(Action action, String propertyName) Updates the combobox's state in response to property changes in associated action.voidAdds anActionListener.voidAdds an item to the item list.voidaddItemListener(ItemListener aListener) Adds anItemListener.voidAdds aPopupMenulistener which will listen to notification messages from the popup portion of the combo box.voidconfigureEditor(ComboBoxEditor anEditor, Object anItem) Initializes the editor with the specified item.protected voidSets the properties on this combobox to match those in the specifiedAction.voidThis method is public as an implementation side effect.protected PropertyChangeListenerCreates and returns aPropertyChangeListenerthat is responsible for listening for changes from the specifiedActionand updating the appropriate properties.protected JComboBox.KeySelectionManagerReturns an instance of the default key-selection manager.protected voidNotifies all listeners that have registered interest for notification on this event type.protected voidNotifies all listeners that have registered interest for notification on this event type.voidNotifiesPopupMenuListeners that the popup portion of the combo box has been canceled.voidNotifiesPopupMenuListeners that the popup portion of the combo box has become invisible.voidNotifiesPopupMenuListeners that the popup portion of the combo box will become visible.Gets the AccessibleContext associated with this JComboBox.Returns the currently setActionfor thisActionEventsource, ornullif noActionis set.Returns the action command that is included in the event sent to action listeners.Returns an array of all theActionListeners added to this JComboBox with addActionListener().Returns the editor used to paint and edit the selected item in theJComboBoxfield.getItemAt(int index) Returns the list item at the specified index.intReturns the number of items in the list.Returns an array of all theItemListeners added to this JComboBox with addItemListener().Returns the list's key-selection manager.intReturns the maximum number of items the combo box can display without a scrollbargetModel()Returns the data model currently used by theJComboBox.Returns an array of all thePopupMenuListeners added to this JComboBox with addPopupMenuListener().Returns the "prototypical display" value - an Object used for the calculation of the display height and width.ListCellRenderer<? super E> Returns the renderer used to display the selected item in theJComboBoxfield.intReturns the first item in the list that matches the given item.Returns the current selected item.Object[]Returns an array containing the selected item.getUI()Returns the L&F object that renders this component.Returns the name of the L&F class that renders this component.voidCauses the combo box to close its popup window.voidinsertItemAt(E item, int index) Inserts an item into the item list at a given index.protected voidRegisters ancestor listener so that it will receiveAncestorEventswhen it or any of its ancestors move or are made visible or invisible.voidThis method is public as an implementation side effect.voidThis method is public as an implementation side effect.booleanReturns true if theJComboBoxis editable.booleanGets the value of thelightWeightPopupEnabledproperty.booleanDetermines the visibility of the popup.protected StringReturns a string representation of thisJComboBox.voidHandlesKeyEvents, looking for the Tab key.voidRemoves anActionListener.voidRemoves all items from the item list.voidremoveItem(Object anObject) Removes an item from the item list.voidremoveItemAt(int anIndex) Removes the item atanIndexThis method works only if theJComboBoxuses a mutable data model.voidremoveItemListener(ItemListener aListener) Removes anItemListener.voidRemoves aPopupMenuListener.protected voidThis protected method is implementation specific.booleanselectWithKeyChar(char keyChar) Selects the list item that corresponds to the specified keyboard character and returns true, if there is an item corresponding to that character.voidSets theActionfor theActionEventsource.voidsetActionCommand(String aCommand) Sets the action command that should be included in the event sent to action listeners.voidsetEditable(boolean aFlag) Determines whether theJComboBoxfield is editable.voidsetEditor(ComboBoxEditor anEditor) Sets the editor used to paint and edit the selected item in theJComboBoxfield.voidsetEnabled(boolean b) Enables the combo box so that items can be selected.voidSets the object that translates a keyboard character into a list selection.voidsetLightWeightPopupEnabled(boolean aFlag) Sets thelightWeightPopupEnabledproperty, which provides a hint as to whether or not a lightweightComponentshould be used to contain theJComboBox, versus a heavyweightComponentsuch as aPanelor aWindow.voidsetMaximumRowCount(int count) Sets the maximum number of rows theJComboBoxdisplays.voidsetModel(ComboBoxModel<E> aModel) Sets the data model that theJComboBoxuses to obtain the list of items.voidsetPopupVisible(boolean v) Sets the visibility of the popup.voidsetPrototypeDisplayValue(E prototypeDisplayValue) Sets the prototype display value used to calculate the size of the display for the UI portion.voidsetRenderer(ListCellRenderer<? super E> aRenderer) Sets the renderer that paints the list items and the item selected from the list in the JComboBox field.voidsetSelectedIndex(int anIndex) Selects the item at indexanIndex.voidsetSelectedItem(Object anObject) Sets the selected item in the combo box display area to the object in the argument.voidsetUI(ComboBoxUI ui) Sets the L&F object that renders this component.voidCauses the combo box to display its popup window.voidupdateUI()Resets the UI property to a value from the current look and feel.Methods declared in class javax.swing.JComponent
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, updateMethods declared in class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTreeMethods declared in class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
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Field Details
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dataModel
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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renderer
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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editor
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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maximumRowCount
protected int maximumRowCountThis protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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isEditable
protected boolean isEditableThis protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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keySelectionManager
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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actionCommand
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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lightWeightPopupEnabled
protected boolean lightWeightPopupEnabledThis protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
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selectedItemReminder
This protected field is implementation specific. Do not access directly or override.
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Constructor Details
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JComboBox
Creates aJComboBoxthat takes its items from an existingComboBoxModel. Since theComboBoxModelis provided, a combo box created using this constructor does not create a default combo box model and may impact how the insert, remove and add methods behave.- Parameters:
aModel- theComboBoxModelthat provides the displayed list of items- See Also:
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JComboBox
Creates aJComboBoxthat contains the elements in the specified array. By default the first item in the array (and therefore the data model) becomes selected.- Parameters:
items- an array of objects to insert into the combo box- See Also:
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JComboBox
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JComboBox
public JComboBox()Creates aJComboBoxwith a default data model. The default data model is an empty list of objects. UseaddItemto add items. By default the first item in the data model becomes selected.- See Also:
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Method Details
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installAncestorListener
protected void installAncestorListener()Registers ancestor listener so that it will receiveAncestorEventswhen it or any of its ancestors move or are made visible or invisible. Events are also sent when the component or its ancestors are added or removed from the containment hierarchy. -
setUI
@BeanProperty(hidden=true, visualUpdate=true, description="The UI object that implements the Component's LookAndFeel.") public void setUI(ComboBoxUI ui) Sets the L&F object that renders this component.- Parameters:
ui- theComboBoxUIL&F object- See Also:
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updateUI
public void updateUI()Resets the UI property to a value from the current look and feel.- Overrides:
updateUIin classJComponent- See Also:
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getUIClassID
Returns the name of the L&F class that renders this component.- Overrides:
getUIClassIDin classJComponent- Returns:
- the string "ComboBoxUI"
- See Also:
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getUI
Returns the L&F object that renders this component.- Overrides:
getUIin classJComponent- Returns:
- the ComboBoxUI object that renders this component
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setModel
@BeanProperty(description="Model that the combo box uses to get data to display.") public void setModel(ComboBoxModel<E> aModel) Sets the data model that theJComboBoxuses to obtain the list of items.- Parameters:
aModel- theComboBoxModelthat provides the displayed list of items
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getModel
Returns the data model currently used by theJComboBox.- Returns:
- the
ComboBoxModelthat provides the displayed list of items
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setLightWeightPopupEnabled
@BeanProperty(expert=true, description="Set to <code>false</code> to require heavyweight popups.") public void setLightWeightPopupEnabled(boolean aFlag) Sets thelightWeightPopupEnabledproperty, which provides a hint as to whether or not a lightweightComponentshould be used to contain theJComboBox, versus a heavyweightComponentsuch as aPanelor aWindow. The decision of lightweight versus heavyweight is ultimately up to theJComboBox. Lightweight windows are more efficient than heavyweight windows, but lightweight and heavyweight components do not mix well in a GUI. If your application mixes lightweight and heavyweight components, you should disable lightweight popups. The default value for thelightWeightPopupEnabledproperty istrue, unless otherwise specified by the look and feel. Some look and feels always use heavyweight popups, no matter what the value of this property.See the article Mixing Heavy and Light Components This method fires a property changed event.
- Parameters:
aFlag- iftrue, lightweight popups are desired
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isLightWeightPopupEnabled
public boolean isLightWeightPopupEnabled()Gets the value of thelightWeightPopupEnabledproperty.- Returns:
- the value of the
lightWeightPopupEnabledproperty - See Also:
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setEditable
@BeanProperty(preferred=true, description="If true, the user can type a new value in the combo box.") public void setEditable(boolean aFlag) Determines whether theJComboBoxfield is editable. An editableJComboBoxallows the user to type into the field or selected an item from the list to initialize the field, after which it can be edited. (The editing affects only the field, the list item remains intact.) A non editableJComboBoxdisplays the selected item in the field, but the selection cannot be modified.- Parameters:
aFlag- a boolean value, where true indicates that the field is editable
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isEditable
public boolean isEditable()Returns true if theJComboBoxis editable. By default, a combo box is not editable.- Returns:
- true if the
JComboBoxis editable, else false
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setMaximumRowCount
@BeanProperty(preferred=true, description="The maximum number of rows the popup should have") public void setMaximumRowCount(int count) Sets the maximum number of rows theJComboBoxdisplays. If the number of objects in the model is greater than count, the combo box uses a scrollbar.- Parameters:
count- an integer specifying the maximum number of items to display in the list before using a scrollbar
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getMaximumRowCount
public int getMaximumRowCount()Returns the maximum number of items the combo box can display without a scrollbar- Returns:
- an integer specifying the maximum number of items that are displayed in the list before using a scrollbar
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setRenderer
@BeanProperty(expert=true, description="The renderer that paints the item selected in the list.") public void setRenderer(ListCellRenderer<? super E> aRenderer) Sets the renderer that paints the list items and the item selected from the list in the JComboBox field. The renderer is used if the JComboBox is not editable. If it is editable, the editor is used to render and edit the selected item.The default renderer displays a string or an icon. Other renderers can handle graphic images and composite items.
To display the selected item,
aRenderer.getListCellRendererComponentis called, passing the list object and an index of -1.- Parameters:
aRenderer- theListCellRendererthat displays the selected item- See Also:
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getRenderer
Returns the renderer used to display the selected item in theJComboBoxfield.- Returns:
- the
ListCellRendererthat displays the selected item.
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setEditor
@BeanProperty(expert=true, description="The editor that combo box uses to edit the current value") public void setEditor(ComboBoxEditor anEditor) Sets the editor used to paint and edit the selected item in theJComboBoxfield. The editor is used only if the receivingJComboBoxis editable. If not editable, the combo box uses the renderer to paint the selected item.- Parameters:
anEditor- theComboBoxEditorthat displays the selected item- See Also:
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getEditor
Returns the editor used to paint and edit the selected item in theJComboBoxfield.- Returns:
- the
ComboBoxEditorthat displays the selected item
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setSelectedItem
@BeanProperty(bound=false, preferred=true, description="Sets the selected item in the JComboBox.") public void setSelectedItem(Object anObject) Sets the selected item in the combo box display area to the object in the argument. IfanObjectis in the list, the display area showsanObjectselected.If
anObjectis not in the list and the combo box is uneditable, it will not change the current selection. For editable combo boxes, the selection will change toanObject.If this constitutes a change in the selected item,
ItemListeners added to the combo box will be notified with one or twoItemEvents. If there is a current selected item, anItemEventwill be fired and the state change will beItemEvent.DESELECTED. IfanObjectis in the list and is not currently selected then anItemEventwill be fired and the state change will beItemEvent.SELECTED.ActionListeners added to the combo box will be notified with anActionEventwhen this method is called.- Parameters:
anObject- the list object to select; usenullto clear the selection
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getSelectedItem
Returns the current selected item.If the combo box is editable, then this value may not have been added to the combo box with
addItem,insertItemAtor the data constructors.- Returns:
- the current selected Object
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setSelectedIndex
@BeanProperty(bound=false, preferred=true, description="The item at index is selected.") public void setSelectedIndex(int anIndex) Selects the item at indexanIndex.- Parameters:
anIndex- an integer specifying the list item to select, where 0 specifies the first item in the list and -1 indicates no selection- Throws:
IllegalArgumentException- ifanIndex< -1 oranIndexis greater than or equal to size
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getSelectedIndex
public int getSelectedIndex()Returns the first item in the list that matches the given item. The result is not always defined if theJComboBoxallows selected items that are not in the list. Returns -1 if there is no selected item or if the user specified an item which is not in the list.- Returns:
- an integer specifying the currently selected list item, where 0 specifies the first item in the list; or -1 if no item is selected or if the currently selected item is not in the list
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getPrototypeDisplayValue
Returns the "prototypical display" value - an Object used for the calculation of the display height and width.- Returns:
- the value of the
prototypeDisplayValueproperty - Since:
- 1.4
- See Also:
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setPrototypeDisplayValue
@BeanProperty(visualUpdate=true, description="The display prototype value, used to compute display width and height.") public void setPrototypeDisplayValue(E prototypeDisplayValue) Sets the prototype display value used to calculate the size of the display for the UI portion.If a prototype display value is specified, the preferred size of the combo box is calculated by configuring the renderer with the prototype display value and obtaining its preferred size. Specifying the preferred display value is often useful when the combo box will be displaying large amounts of data. If no prototype display value has been specified, the renderer must be configured for each value from the model and its preferred size obtained, which can be relatively expensive.
- Parameters:
prototypeDisplayValue- the prototype display value- Since:
- 1.4
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addItem
Adds an item to the item list. This method works only if theJComboBoxuses a mutable data model.Warning: Focus and keyboard navigation problems may arise if you add duplicate String objects. A workaround is to add new objects instead of String objects and make sure that the toString() method is defined. For example:
comboBox.addItem(makeObj("Item 1")); comboBox.addItem(makeObj("Item 1")); ... private Object makeObj(final String item) { return new Object() { public String toString() { return item; } }; }- Parameters:
item- the item to add to the list- See Also:
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insertItemAt
Inserts an item into the item list at a given index. This method works only if theJComboBoxuses a mutable data model.- Parameters:
item- the item to add to the listindex- an integer specifying the position at which to add the item- See Also:
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removeItem
Removes an item from the item list. This method works only if theJComboBoxuses a mutable data model.- Parameters:
anObject- the object to remove from the item list- See Also:
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removeItemAt
public void removeItemAt(int anIndex) Removes the item atanIndexThis method works only if theJComboBoxuses a mutable data model.- Parameters:
anIndex- an int specifying the index of the item to remove, where 0 indicates the first item in the list- See Also:
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removeAllItems
public void removeAllItems()Removes all items from the item list. -
showPopup
public void showPopup()Causes the combo box to display its popup window.- See Also:
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hidePopup
public void hidePopup()Causes the combo box to close its popup window.- See Also:
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setPopupVisible
public void setPopupVisible(boolean v) Sets the visibility of the popup.- Parameters:
v- iftrueshows the popup, otherwise, hides the popup.
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isPopupVisible
public boolean isPopupVisible()Determines the visibility of the popup.- Returns:
- true if the popup is visible, otherwise returns false
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addItemListener
Adds anItemListener.aListenerwill receive one or twoItemEvents when the selected item changes.- Specified by:
addItemListenerin interfaceItemSelectable- Parameters:
aListener- theItemListenerthat is to be notified- See Also:
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removeItemListener
Removes anItemListener.- Specified by:
removeItemListenerin interfaceItemSelectable- Parameters:
aListener- theItemListenerto remove- See Also:
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getItemListeners
Returns an array of all theItemListeners added to this JComboBox with addItemListener().- Returns:
- all of the
ItemListeners added or an empty array if no listeners have been added - Since:
- 1.4
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addActionListener
Adds anActionListener.The
ActionListenerwill receive anActionEventwhen a selection has been made. If the combo box is editable, then anActionEventwill be fired when editing has stopped.- Parameters:
l- theActionListenerthat is to be notified- See Also:
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removeActionListener
Removes anActionListener.- Parameters:
l- theActionListenerto remove
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getActionListeners
Returns an array of all theActionListeners added to this JComboBox with addActionListener().- Returns:
- all of the
ActionListeners added or an empty array if no listeners have been added - Since:
- 1.4
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addPopupMenuListener
Adds aPopupMenulistener which will listen to notification messages from the popup portion of the combo box.For all standard look and feels shipped with Java, the popup list portion of combo box is implemented as a
JPopupMenu. A custom look and feel may not implement it this way and will therefore not receive the notification.- Parameters:
l- thePopupMenuListenerto add- Since:
- 1.4
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removePopupMenuListener
Removes aPopupMenuListener.- Parameters:
l- thePopupMenuListenerto remove- Since:
- 1.4
- See Also:
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getPopupMenuListeners
Returns an array of all thePopupMenuListeners added to this JComboBox with addPopupMenuListener().- Returns:
- all of the
PopupMenuListeners added or an empty array if no listeners have been added - Since:
- 1.4
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firePopupMenuWillBecomeVisible
public void firePopupMenuWillBecomeVisible()NotifiesPopupMenuListeners that the popup portion of the combo box will become visible.This method is public but should not be called by anything other than the UI delegate.
- Since:
- 1.4
- See Also:
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firePopupMenuWillBecomeInvisible
public void firePopupMenuWillBecomeInvisible()NotifiesPopupMenuListeners that the popup portion of the combo box has become invisible.This method is public but should not be called by anything other than the UI delegate.
- Since:
- 1.4
- See Also:
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firePopupMenuCanceled
public void firePopupMenuCanceled()NotifiesPopupMenuListeners that the popup portion of the combo box has been canceled.This method is public but should not be called by anything other than the UI delegate.
- Since:
- 1.4
- See Also:
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setActionCommand
Sets the action command that should be included in the event sent to action listeners.- Parameters:
aCommand- a string containing the "command" that is sent to action listeners; the same listener can then do different things depending on the command it receives
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getActionCommand
Returns the action command that is included in the event sent to action listeners.- Returns:
- the string containing the "command" that is sent to action listeners.
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setAction
@BeanProperty(visualUpdate=true, description="the Action instance connected with this ActionEvent source") public void setAction(Action a) Sets theActionfor theActionEventsource. The newActionreplaces any previously setActionbut does not affectActionListenersindependently added withaddActionListener. If theActionis already a registeredActionListenerfor theActionEventsource, it is not re-registered.Setting the
Actionresults in immediately changing all the properties described in Swing Components SupportingAction. Subsequently, the combobox's properties are automatically updated as theAction's properties change.This method uses three other methods to set and help track the
Action's property values. It uses theconfigurePropertiesFromActionmethod to immediately change the combobox's properties. To track changes in theAction's property values, this method registers thePropertyChangeListenerreturned bycreateActionPropertyChangeListener. The defaultPropertyChangeListenerinvokes theactionPropertyChangedmethod when a property in theActionchanges.- Parameters:
a- theActionfor theJComboBox, ornull.- Since:
- 1.3
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getAction
Returns the currently setActionfor thisActionEventsource, ornullif noActionis set.- Returns:
- the
Actionfor thisActionEventsource; ornull - Since:
- 1.3
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configurePropertiesFromAction
Sets the properties on this combobox to match those in the specifiedAction. Refer to Swing Components SupportingActionfor more details as to which properties this sets.- Parameters:
a- theActionfrom which to get the properties, ornull- Since:
- 1.3
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createActionPropertyChangeListener
Creates and returns aPropertyChangeListenerthat is responsible for listening for changes from the specifiedActionand updating the appropriate properties.Warning: If you subclass this do not create an anonymous inner class. If you do the lifetime of the combobox will be tied to that of the
Action.- Parameters:
a- the combobox's action- Returns:
- the
PropertyChangeListener - Since:
- 1.3
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actionPropertyChanged
Updates the combobox's state in response to property changes in associated action. This method is invoked from thePropertyChangeListenerreturned fromcreateActionPropertyChangeListener. Subclasses do not normally need to invoke this. Subclasses that support additionalActionproperties should override this andconfigurePropertiesFromAction.Refer to the table at Swing Components Supporting
Actionfor a list of the properties this method sets.- Parameters:
action- theActionassociated with this comboboxpropertyName- the name of the property that changed- Since:
- 1.6
- See Also:
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fireItemStateChanged
Notifies all listeners that have registered interest for notification on this event type.- Parameters:
e- the event of interest- See Also:
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fireActionEvent
protected void fireActionEvent()Notifies all listeners that have registered interest for notification on this event type.- See Also:
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selectedItemChanged
protected void selectedItemChanged()This protected method is implementation specific. Do not access directly or override. -
getSelectedObjects
Returns an array containing the selected item. This method is implemented for compatibility withItemSelectable.- Specified by:
getSelectedObjectsin interfaceItemSelectable- Returns:
- an array of
Objectscontaining one element -- the selected item
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actionPerformed
This method is public as an implementation side effect. do not call or override.- Specified by:
actionPerformedin interfaceActionListener- Parameters:
e- the event to be processed
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contentsChanged
This method is public as an implementation side effect. do not call or override.- Specified by:
contentsChangedin interfaceListDataListener- Parameters:
e- aListDataEventencapsulating the event information
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intervalAdded
This method is public as an implementation side effect. do not call or override.- Specified by:
intervalAddedin interfaceListDataListener- Parameters:
e- aListDataEventencapsulating the event information
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intervalRemoved
This method is public as an implementation side effect. do not call or override.- Specified by:
intervalRemovedin interfaceListDataListener- Parameters:
e- aListDataEventencapsulating the event information
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selectWithKeyChar
public boolean selectWithKeyChar(char keyChar) Selects the list item that corresponds to the specified keyboard character and returns true, if there is an item corresponding to that character. Otherwise, returns false.- Parameters:
keyChar- a char, typically this is a keyboard key typed by the user- Returns:
trueif there is an item corresponding to that character. Otherwise, returnsfalse.
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setEnabled
@BeanProperty(preferred=true, description="The enabled state of the component.") public void setEnabled(boolean b) Enables the combo box so that items can be selected. When the combo box is disabled, items cannot be selected and values cannot be typed into its field (if it is editable).- Overrides:
setEnabledin classJComponent- Parameters:
b- a boolean value, where true enables the component and false disables it- See Also:
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configureEditor
Initializes the editor with the specified item.- Parameters:
anEditor- theComboBoxEditorthat displays the list item in the combo box field and allows it to be editedanItem- the object to display and edit in the field
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processKeyEvent
HandlesKeyEvents, looking for the Tab key. If the Tab key is found, the popup window is closed.- Overrides:
processKeyEventin classJComponent- Parameters:
e- theKeyEventcontaining the keyboard key that was pressed- See Also:
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setKeySelectionManager
@BeanProperty(bound=false, expert=true, description="The objects that changes the selection when a key is pressed.") public void setKeySelectionManager(JComboBox.KeySelectionManager aManager) Sets the object that translates a keyboard character into a list selection. Typically, the first selection with a matching first character becomes the selected item.- Parameters:
aManager- a key selection manager
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getKeySelectionManager
Returns the list's key-selection manager.- Returns:
- the
KeySelectionManagercurrently in use
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getItemCount
Returns the number of items in the list.- Returns:
- an integer equal to the number of items in the list
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getItemAt
Returns the list item at the specified index. Ifindexis out of range (less than zero or greater than or equal to size) it will returnnull.- Parameters:
index- an integer indicating the list position, where the first item starts at zero- Returns:
- the item at that list position; or
nullif out of range
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createDefaultKeySelectionManager
Returns an instance of the default key-selection manager.- Returns:
- the
KeySelectionManagercurrently used by the list - See Also:
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paramString
Returns a string representation of thisJComboBox. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not benull.- Overrides:
paramStringin classJComponent- Returns:
- a string representation of this
JComboBox
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getAccessibleContext
Gets the AccessibleContext associated with this JComboBox. For combo boxes, the AccessibleContext takes the form of an AccessibleJComboBox. A new AccessibleJComboBox instance is created if necessary.- Specified by:
getAccessibleContextin interfaceAccessible- Overrides:
getAccessibleContextin classComponent- Returns:
- an AccessibleJComboBox that serves as the AccessibleContext of this JComboBox
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